PROJECT SUMMARY The goal of administrative supplementary project is to expand the existing R21 award in NIBIB on developing wearable ultrasonic device for small joints imaging to focus on chronic noninvasive neuromodulation for treating and alleviating Alzheimer?s disease and its related dementias (ADRD). Noninvasive neuromodulation provides a safe, convenient, and low-cost alternative to conventional invasive approaches. Among these noninvasive approaches, ultrasound has high spatial resolution and can penetrate to deep brain regions with high spatiotemporal resolution, in comparison with transcranial magnetic simulation (TMS) and transcranial direction current stimulation (tDCS). However, existing transcranial ultrasound devices present these following challenges. First, these devices are bulky and are only available in centralized hospitals. Second, they are rigid and do not conform to skulls with different sizes and shapes. Third, these devices are often composed of a small number of transducers that require high transmission power to compensate the skull attenuation and achieve effective modulation in the brain. We propose to design and develop a stretchable ultrasonic transducer array that will overcome all of these challenges. First, it has low form factors that allow portable and chronic neuromodulation on the go. Second, it is soft and can adapt to every skull of different sizes and shapes. Third, it is composed of a large array of transducers that allow low transmission power of each transducer and still maintain substantial modulation intensity in the focused deep regions. Additionally, the phased array control mechanism will enable steering the beam and stimulating the brain at any region on demand. If successful, it will enable treating and alleviating neurological disorders such as ADRD in real time, greatly improving the treating efficiency and outcome.